1. Field of the Invention
The disclosures herein relate to a pixel unit and an imaging device.
2. Description of the Related Art
Solid-state imaging devices such as CMOS (i.e., complementary metal-oxide semiconductor) imaging sensors are manufactured by use of a typical semiconductor manufacturing process. A single chip may be configured to have both an analog circuit and a digital circuit implemented therein. Significant advantages such as reduction of the number of peripheral ICs may thus be achievable.
A solid-state imaging device includes a pixel unit having a plurality of arranged pixels and peripheral circuits disposed in the surrounding area of the pixel unit. Each pixel includes a photoelectric conversion element (PD) such as a photodiode, pixel transistors of various types, and a floating diffusion (FD) region for converting electric charge obtained through photoelectric conversion into voltage. A transfer transistor (TX) included in the pixel transistors has a transfer gate (TG) for transferring electric charge from the PD region to the FD region for read-out.
Some related-art solid-state imaging devices have a structure characterized by an extended part which is formed by extending a portion of the gate of a transfer transistor from the main part of the gate toward the PD region.